A platinum / tungsten trioxide / silicoaluminate composite and its preparation method and application

Abstract

The present invention relates to a platinum / tungsten trioxide / silicoaluminate composite, a preparation method thereof and an application thereof. In the present invention, a platinum colloid and a tungsten trioxide colloid are respectively prepared, and then the platinum colloid and the tungsten trioxide colloid are mixed and silicon aluminate is added thereto to obtain the platinum / tungsten trioxide / silicoaluminate composite. The preparation method is very simple, easy to repeat and control; in the platinum / tungsten trioxide / silicoaluminate composite prepared by the present invention, there is a good combination between platinum nanoparticles and tungsten trioxide nanoparticles. When used as a catalyst in the selective hydrogenolysis reaction of polyols, it has a higher polyol conversion rate and selectivity, and good repeatability.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite catalysts, and particularly relates to a platinum / tungsten trioxide / silicoaluminate oxide composite and a preparation method and application thereof. Background Art

[0002] Glycerol (propanetriol) belongs to the simplest polyol, and its selectively hydrogenolyzed products 1,3-propanediol and 1,2-propanediol have very important industrial uses. Among them, 1,3-propanediol is an important monomer for producing polytrimethylene terephthalate (PTT), and the obtained PTT has excellent resilience, dyeability, biodegradability, etc., and has broad prospects in industries such as carpets and textile engineering plastics.

[0003] At present, the industrial production method of 1,3-propanediol is mainly the biological fermentation method of DuPont Company. This method has low production efficiency, and due to the low product concentration, the energy consumption required for purifying and separating 1,3-propanediol is very high. There are also production methods of 1,3-propanediol in China. For example, the acrolein hydration method (Chinese Patent CN93114516.3) uses gaseous glycerol hydrate to dehydrate to form acrolein under a solid acid catalyst, and the formed acrolein hydrates to form 3-hydroxypropionaldehyde under the action of an acidic catalyst, and the formed 3-hydroxypropionaldehyde is hydrogenated under a conventional hydrogenation catalyst to prepare 1,3-propanediol, while by-producing 1,2-propanediol. This method has low efficiency and requires many steps to obtain the product.

[0004] In addition, relevant literature has reported a method for directly obtaining 1,3-propanediol from glycerol, which is currently the most ideal and economical method.

[0005] The literature (Catal.Commun.2008,9,1360-1363) reported a method for preparing 1,3-propanediol by hydrogenolysis of glycerol using 1,3-dimethyl-2-imidazolidinone as a solvent. The yield of 1,3-propanediol in this method is 24%. The Tomishige research group in Japan added liquid sulfuric acid (H 2 / Re = 1) under the action of an Ir-Re / SiO + catalyst. At an initial hydrogen pressure of 8 MPa and a reaction temperature of 120 °C, after reacting for 36 h in a 20% glycerol aqueous solution, 1,3-propanediol was obtained, and its yield was as high as 38.0%. Jinhooh in South Korea reported that Pt was supported on sulfuric acid-acidified ZrO 2 and reacted in DMI as a reaction medium at an initial hydrogen pressure of 7.3 MPa and a reaction temperature of 170 °C for 24 h to obtain 1,3-propanediol, and its yield was as high as 55.6%. In the above reaction system for preparing 1,3-propanediol, an organic solvent was used as the reaction medium, and the added liquid acid was also very unfavorable for the reuse of the catalyst. More importantly, the product was difficult to separate from other substances.

[0006] The platinum / tungsten trioxide system can be used as a solid catalyst to directly catalyze the conversion of glycerol into 1,3-propanediol, avoiding the use of organic solvents as reaction media and eliminating the need to add liquid acids.

[0007] The literature (Chin.J.Catal.2012,33:1257-1261) reported a simple Pt / mesoporous WO 3 A catalyst directly used for the hydrogenolysis of glycerol to 1,3-propanediol, but the overall yield of 1,3-propanediol is still low. According to the results of mechanism studies, the interfacial synergistic effect between platinum and tungsten trioxide is very important for the formation of 1,3-propanediol. However, the current preparation methods are mainly impregnation methods, where platinum and tungsten trioxide are separately loaded or simultaneously loaded on a support, and a platinum-tungsten oxide-support catalyst is obtained through high-temperature calcination. On the one hand, high-temperature calcination will cause the platinum particle size to increase. On the other hand, the combination between platinum and tungsten trioxide is random, and a good combination between platinum and tungsten trioxide is not necessarily formed, resulting in low selectivity for 1,3-propanediol. In addition, due to inappropriate preparation methods, the obtained catalyst has a large structural randomness and poor repeatability.

[0008] To solve the problems of low combination probability between platinum and tungsten trioxide in the platinum-tungsten trioxide catalyst and poor repeatability of catalyst performance, a new preparation method for the platinum-tungsten trioxide catalyst needs to be developed. Summary of the Invention

[0009] The object of the present invention is to provide a preparation method for a platinum / tungsten trioxide / silicoaluminate oxide composite, enabling good combination between platinum and tungsten trioxide, with high selectivity for 1,3-propanediol when applied in the selective hydrogenolysis of glycerol, and excellent repeatability of catalyst performance.

[0010] The technical solution adopted by the present invention to solve the above problems is: a preparation method for a platinum / tungsten trioxide / silicoaluminate oxide composite, comprising the following steps:

[0011] (1) Preparation of platinum colloid: Dissolve a platinum salt in ethylene glycol to obtain solution A, dissolve sodium hydroxide in ethylene glycol to obtain solution B. Under stirring conditions, mix solution A and solution B evenly, adjust the pH value of the solution to 7-13, heat it to 120-190 °C under the protection of an inert gas atmosphere and keep it for 0.5-24 h, and obtain a platinum nano-colloid solution after cooling.

[0012] (2) Preparation of tungsten trioxide colloid: Dissolve tungsten hexachloride in anhydrous solvent C, slowly add a water-containing solvent D, and when the solution turns from yellow to colorless or light blue, tungsten trioxide colloid is obtained.

[0013] (3) After mixing the platinum colloid and the tungsten trioxide colloid and stirring for a certain period of time, add the silica-alumina oxide. After the platinum colloid and the tungsten trioxide colloid are loaded on the silica-alumina oxide, separate the solid substance from the liquid to obtain the solid, i.e., the platinum / tungsten trioxide / silica-alumina oxide composite.

[0014] Preferably, the platinum salt described in step (1) is at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, and platinum acetate.

[0015] Preferably, both solvent C and solvent D described in step (2) are one or more of methanol, ethanol, propanol, butanol, ethylene glycol, and N,N-dimethylformamide.

[0016] Preferably, the mass ratio of the platinum colloid to the tungsten trioxide colloid is 1:0.05 to 1:50; the mass ratio of the platinum colloid to the silica-alumina oxide is 0.0005 to 0.20:1.

[0017] More preferably, the mass ratio of the platinum colloid to the tungsten trioxide colloid is 1:0.5 to 1:10; the mass ratio of the platinum colloid to the silica-alumina oxide is 0.001 to 0.10:1.

[0018] Even more preferably, the mass ratio of the platinum colloid to the tungsten trioxide colloid is 1:2 to 1:5; the mass ratio of the platinum colloid to the silica-alumina oxide is 0.005 to 0.05:1.

[0019] Preferably, the silica-alumina oxide is amorphous silica-alumina or a silica-alumina molecular sieve.

[0020] More preferably, the amorphous silica-alumina is a composite composed of silica and alumina, where alumina accounts for 3% to 30% of the total mass of the composite; the silica-alumina molecular sieve is ZSM-5, NaX, or NaY.

[0021] Another object of the present invention is to provide a platinum / tungsten trioxide / silica-alumina oxide composite, which is prepared by the above-mentioned method for preparing a platinum / tungsten trioxide / silica-alumina oxide composite.

[0022] Preferably, the mass percentage of platinum in the platinum / tungsten trioxide / silica-alumina oxide composite is 0.1% to 5%, and the mass percentage of tungsten trioxide is 2% to 40%.

[0023] More preferably, the mass percentage of platinum in the platinum / tungsten trioxide / silica-alumina oxide composite is 0.5% to 2%, and the mass percentage of tungsten trioxide is 5% to 20%.

[0024] Another object of the present invention is to provide an application of the platinum / tungsten trioxide / silica-alumina oxide composite, and the application of the platinum / tungsten trioxide / silica-alumina oxide composite in the selective hydrogenolysis reaction of polyols.

[0025] Preferably, the polyol is glycerol, erythritol, pentaerythritol or hexitol.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] (1) In the present invention, platinum colloid and tungsten trioxide colloid are respectively prepared, and then the platinum colloid and tungsten trioxide colloid are mixed and added with silica-alumina oxide to obtain a platinum / tungsten trioxide / silica-alumina oxide composite. The assembly of platinum colloid and tungsten trioxide colloid improves the binding probability between platinum and tungsten trioxide; the particle sizes of platinum and tungsten trioxide are small, and they are pre-shaped before binding instead of randomly forming on the carrier, which improves the utilization efficiency of platinum and tungsten trioxide; the formed platinum / tungsten trioxide composite is assembled on the carrier, avoiding the high-temperature treatment required by traditional catalyst preparation techniques and preventing the growth of platinum particles and tungsten trioxide particles.

[0028] (2) The preparation method of the platinum / tungsten trioxide / silica-alumina oxide composite of the present invention is very simple, easy to repeat and control, and there is a good binding between platinum nanoparticles and tungsten trioxide nanoparticles in the prepared platinum / tungsten trioxide / silica-alumina oxide composite catalyst. The catalyst has good repeatability and higher polyol conversion rate and selectivity compared with the existing catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a high-resolution transmission electron microscope image of the composite catalysts obtained in Example 1, Comparative Example 1 and Comparative Example 2 of the present invention.

[0030] Among them: (a) is the high-resolution transmission electron microscope image of the composite catalyst obtained in Example 1, (b) is the high-resolution transmission electron microscope image of the composite catalyst obtained in Comparative Example 1, and (c) is the high-resolution transmission electron microscope image of the composite catalyst obtained in Comparative Example 2.

[0031] Figure 2 It is a scanning transmission electron microscope image STEM of the composite catalyst obtained in Example 1 of the present invention.

[0032] Among them: (a) is the scanning transmission electron microscope image STEM of the composite catalyst obtained in Example 1 of the present invention, (b) is the imaging diagram of element Pt in the marked area A in Figure (a), (c) is the imaging diagram of element W in the marked area A in Figure (a), and (d) is the superimposed diagram of Figure (a) and Figure (b).

[0033] Figure 3 It is a glycerol hydrogenolysis performance diagram of platinum / tungsten trioxide / silica-alumina oxide composite catalysts with different W contents.

[0034] Figure 4 It is a glycerol hydrogenolysis performance diagram of platinum / tungsten trioxide / silica-alumina oxide composite catalysts with different Pt contents. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be further described in detail below in conjunction with the embodiments with the accompanying drawings.

[0036] Example 1

[0037] A method for preparing a platinum / tungsten trioxide / silicoaluminate oxide composite, comprising the following steps:

[0038] (1) Preparation of platinum colloid: First, dissolve 1.0 g of H 2 PtCl 6 •6H 2 O (platinum content ≥ 37.0%) in 100 mL of ethylene glycol, stir at room temperature for 10 min. After complete dissolution, add 50 mL of NaOH / ethylene glycol (0.25 mol / L) solution, continue to stir at room temperature for 30 min, adjust the pH value of the solution to 10, introduce argon for protection, use an electric heating mantle to heat up to 160 °C, react for 3 hours, and naturally cool down under inert gas protection to obtain a brownish - brown homogeneous and stable "non - protected" Pt colloid.

[0039] (2) Preparation of tungsten trioxide colloid: Dissolve 0.33 g of WCl 6 in 50 mL of absolute ethanol, stir at room temperature for 20 min. After complete dissolution, add 20 mL of 5% water / ethanol mixed solution, continue to stir and hydrolyze at room temperature. When the solution changes from yellow to colorless, tungsten trioxide colloid is obtained.

[0040] (3) Add the Pt colloid (0.04 g of platinum) to the tungsten trioxide colloid obtained in step (2) (0.2 g of tungsten trioxide), continue to stir for 3 h, add 1.76 g of amorphous silicoaluminate oxide (ASA) and continue to stir for 3 hours. Then, successively perform centrifugation, alternate rinsing with water and ethanol, and freeze - drying to obtain a platinum / tungsten trioxide / silicoaluminate oxide composite (catalyst 2Pt / 10W / ASA), wherein the mass percentage of platinum in the catalyst 2Pt / 10W / ASA is 2%, and the mass percentage of tungsten trioxide is 10% (WO 3 is abbreviated as W in the name).

[0041] The prepared composite catalyst 2Pt / 10W / ASA was characterized by electron microscopy and elemental imaging analysis, as shown in Figure 1 a and Figure 2 respectively. As seen in Figure 1 a, the platinum nanoparticles and tungsten oxide nanoparticles have a tight binding; as shown in Figure 2 , there is also a good binding between the platinum element and the tungsten element.

[0042] Example 2

[0043] A preparation method of a platinum / tungsten trioxide / silicoaluminate composite, comprising the following steps:

[0044] (1) Preparation of platinum colloid: First, dissolve 1.0 g of H 2 PtCl 6 •6H 2 O (platinum content ≥ 37.0%) in 100 mL of ethylene glycol, stir at room temperature for 10 min. After complete dissolution, add 50 mL of NaOH / ethylene glycol (0.25 mol / L) solution, continue to stir at room temperature for 30 min, adjust the pH value of the solution to 13, introduce argon for protection, use an electric heating mantle to heat up to 160 °C, react for 3 hours, and naturally cool down under inert gas protection to obtain a brownish - homogeneous and stable "non - protected" Pt colloid.

[0045] (2) Preparation of tungsten trioxide colloid: Dissolve 0.33 g of WCl 6 in 50 mL of absolute ethanol, stir at room temperature for 20 min. After complete dissolution, add 20 mL of 5% water / ethanol mixed solution, continue to stir and hydrolyze at room temperature. When the solution turns from yellow to colorless, tungsten trioxide colloid is obtained.

[0046] (3) After mixing the platinum colloid (containing 0.04 g of platinum) obtained in step (1) with the tungsten trioxide colloid (containing 0.2 g of tungsten trioxide) obtained in step (2), continue to stir for 3 h, add 1.76 g of molecular sieve ZSM - 5 and continue to stir for 3 h. Then, successively perform centrifugation, alternately rinse with water and ethanol, and freeze - dry to obtain a platinum / tungsten trioxide / silicoaluminate composite (catalyst 2Pt / 10W / ZSM - 5).

[0047] Example 3

[0048] A preparation method of a platinum / tungsten trioxide / silicoaluminate composite, comprising the following steps:

[0049] (1) Preparation of platinum colloid: First, dissolve 1.0 g of H 2 PtCl 6 •6H 2 O (platinum content ≥ 37.0%) in 100 mL of ethylene glycol, stir at room temperature for 10 min. After complete dissolution, add 50 mL of NaOH / ethylene glycol (0.25 mol / L) solution, continue to stir at room temperature for 30 min, adjust the pH value of the solution to 7, introduce argon for protection, use an electric heating mantle to heat up to 160 °C, react for 3 h, and naturally cool down under inert gas protection to obtain a brownish - homogeneous and stable "non - protected" Pt colloid.

[0050] (2) Preparation of tungsten trioxide colloid: Dissolve 0.825 g of WCl 6Dissolve it in 50 mL of anhydrous methanol and stir for 20 min at room temperature. After complete dissolution, add 20 mL of 5% water / propanol mixed solution and continue stirring and hydrolyzing at room temperature. When the solution changes from yellow to colorless, tungsten trioxide colloid is obtained.

[0051] (3) Add Pt colloid (containing 0.01 g of platinum) to the tungsten trioxide colloid obtained in step (2), continue stirring for 3 h, add 20 g of amorphous silica-alumina oxide (ASA) and continue stirring for 3 h. Then, successively perform centrifugation, alternate rinsing with water and ethanol, and freeze-drying to obtain a platinum / tungsten trioxide / silica-alumina oxide composite. The mass ratio of platinum to tungsten trioxide in this composite is 1:50, and the ratio of platinum to ASA is 0.0005:1.

[0052] Example 4

[0053] A preparation method of a platinum / tungsten trioxide / silica-alumina oxide composite, comprising the following steps:

[0054] (1) Preparation of Pt colloid: First, dissolve 1.0 g of H 2 PtCl 6 •6H 2 O (platinum content ≥ 37.0%) in 100 mL of ethylene glycol, stir at room temperature for 10 min. After complete dissolution, add 50 mL of NaOH / ethylene glycol (0.25 mol / L) solution, continue stirring at room temperature for 30 min, adjust the pH value of the solution to 9, introduce argon for protection, use an electric heating mantle to heat up to 160 °C, react for 3 h, and naturally cool down under inert gas protection to obtain a brownish homogeneous and stable "non-protected" Pt colloid.

[0055] (2) Preparation of tungsten trioxide colloid: Dissolve 0.0083 g of WCl 6 in 50 mL of anhydrous N,N-dimethylformamide, stir at room temperature for 20 min. After complete dissolution, add 20 mL of 5% water / butanol mixed solution, continue stirring and hydrolyzing at room temperature. When the solution changes from yellow to colorless, tungsten trioxide colloid is obtained.

[0056] (3) Add Pt colloid (containing 0.1 g of platinum) to the tungsten trioxide colloid obtained in step (2), continue stirring for 3 h, add 0.5 g of amorphous silica-alumina oxide (ASA) and continue stirring for 3 h. Then, successively perform centrifugation, alternate rinsing with water and ethanol, and freeze-drying to obtain a platinum / tungsten trioxide / silica-alumina oxide composite. The mass ratio of platinum to tungsten trioxide in this composite is 1:0.05, and the mass ratio of platinum to ASA is 0.2:1.

[0057] Example 5

[0058] 2Pt / 10W / ASA Catalytic Hydrogenolysis Performance Test

[0059] In an autoclave, 0.5 g of the platinum / tungsten trioxide / silicoaluminoxide composite (catalyst 2Pt / 10W / ASA) prepared in Example 1 was dispersed in 25.0 g of a 4% glycerol / aqueous solution, and 3 MPa of hydrogen was introduced into the autoclave. The temperature was raised to 180 °C, and the catalytic reaction was carried out for 12 h under magnetic stirring (500 rpm). The products were analyzed by gas chromatography. The glycerol conversion was 77%, and the selectivity for 1,3-propanediol was 47%.

[0060] Example 6

[0061] Performance test of 2Pt / 10W / ZSM-5 for glycerol hydrogenolysis

[0062] In an autoclave, 0.5 g of the platinum / tungsten trioxide / silicoaluminoxide composite (catalyst 2Pt / 10W / ZSM-5) prepared in Example 2 was dispersed in 25.0 g of an 8% glycerol / aqueous solution, and 3 MPa of hydrogen was introduced into the autoclave. The temperature was raised to 190 °C, and the catalytic reaction was carried out for 6 h under magnetic stirring (500 rpm). The products were analyzed by gas chromatography. The glycerol conversion was 20%, and the selectivity for 1,3-propanediol was 42%.

[0063] Example 7

[0064] Performance test of 2Pt / 10W / ASA for polyol hydrogenolysis

[0065] 5% erythritol / aqueous solution, 5% xylitol / aqueous solution, and 5% sorbitol / aqueous solution were respectively prepared; 0.5 g of the platinum / tungsten trioxide / silicoaluminoxide composite (2Pt / 10W / ASA catalyst) prepared in Example 1 was respectively mixed with 25 ml of the above three liquids. The reaction conditions were as follows: 6 MPa of hydrogen was introduced into the autoclave, the temperature was raised to 220 °C, and the catalytic reaction was carried out for 24 h under magnetic stirring (600 rpm). The products were analyzed by liquid chromatography. The erythritol conversion was 45%, and the selectivity for 1,4-butanediol was 33%; the xylitol conversion was 22%, and the selectivity for 1,5-pentanediol was 25%; the sorbitol conversion was 18%, and the selectivity for 1,6-hexanediol was 28%. The results show that the prepared platinum-tungsten catalyst can catalyze the conversion of other polyols.

[0066] Comparative Example 1

[0067] (1) 2% of the total mass of the target catalyst of Pt colloid (0.04 g of platinum therein) obtained according to the preparation method of Example 1 was mixed with 1.76 g of amorphous silicoaluminoxide ASA, stirred for 3 h, successively centrifuged, washed alternately with water and ethanol, and freeze-dried to obtain Pt / ASA.

[0068] (2) 0.33 g of WCl 6Dissolve it in 50 mL of absolute ethanol and stir for 20 min at room temperature. After complete dissolution, add 20 mL of 5% water / ethanol mixed solution and continue stirring and hydrolyzing at room temperature. When the solution changes from yellow to colorless, tungsten trioxide colloid is obtained.

[0069] (3) Add the Pt / ASA solid obtained in step (1) to the tungsten trioxide colloid (0.2 g of tungsten trioxide therein) obtained in step (2), continue stirring for 3 h, centrifuge, wash alternately with water and ethanol, and freeze-dry to obtain the catalyst 2Pt / ASA-10W (named according to the assembly order). Its high-resolution electron microscope image is as Figure 1 shown in b, and no effective binding occurs between the platinum nanoparticles and the tungsten oxide nanoparticles.

[0070] Comparative Example 2

[0071] Dissolve 0.33 g of WCl 6 in 50 mL of absolute ethanol and stir for 20 min at room temperature. After complete dissolution, add 20 mL of 5% water / ethanol mixed solution and continue stirring and hydrolyzing at room temperature. When the solution changes from yellow to colorless (i.e., tungsten trioxide colloid is obtained), add 1.76 g of amorphous silica-alumina oxide ASA, stir for 3 h, then add 2% of the total mass of the target catalyst of the Pt colloid (0.04 g of platinum therein) prepared according to the method of Example 1, continue stirring for 3 h, centrifuge in sequence, wash alternately with water and ethanol, and freeze-dry to obtain the catalyst 10W / ASA-2Pt (named according to the assembly order). Its high-resolution electron microscope image is as Figure 1 shown in c, and no effective binding occurs between the platinum nanoparticles and the tungsten oxide nanoparticles.

[0072] Comparative Example 3

[0073] Performance test of 2Pt / ASA-10W and 10W / ASA-2Pt in catalytic glycerol hydrogenolysis

[0074] Under the same reaction conditions as in Example 5, disperse 0.5 g of the catalyst 2Pt / ASA-10W (the catalyst obtained in Comparative Example 1) and 10W / ASA-2Pt (the catalyst obtained in Comparative Example 2) in a high-pressure autoclave containing 25.0 g of 4% glycerol / water solution respectively, and introduce 3 MPa of hydrogen into the high-pressure autoclave. Heat up to 180 °C and carry out the catalytic reaction for 12 h under magnetic stirring (500 rpm). Analyze the products by gas chromatography. For the 10W / ASA-2Pt catalyst, the glycerol conversion rate is 32% and the selectivity for 1,3-propanediol is 24%; for the 2Pt / ASA-10W catalyst, the glycerol conversion rate is 15.6% and the selectivity for 1,3-propanediol is 0%.

[0075] From the results of Example 5 and Comparative Example 3, it can be seen that after platinum is combined with tungsten trioxide, the glycerol conversion rate and 1,3-propanediol selectivity can be improved well.

[0076] To achieve the final research effect of the present invention, the effects of different tungsten loadings and different platinum loadings on the catalytic performance of the catalyst were investigated, taking the catalytic glycerol hydrogenolysis performance as an example.

[0077] (I) Catalytic performance of platinum / tungsten trioxide / silicoaluminate composite catalysts with different tungsten trioxide loadings

[0078] Under the condition of constant platinum loading, the tungsten loading was changed to obtain catalysts of 2Pt / 5W / ASA, 2Pt / 10W / ASA, 2Pt / 15W / ASA, and 2Pt / 20W / ASA. Performance tests were carried out under the same catalytic reaction conditions as in Example 5, and their conversion rates and selectivities are as Figure 3 shown. It can be seen from the experimental results that when the tungsten loading exceeds 10%, the difference in glycerol conversion rate and 1,3-propanediol selectivity is not significant.

[0079] (II) Catalytic performance of platinum / tungsten trioxide / silicoaluminate composite catalysts with different platinum loadings

[0080] Under the condition of constant tungsten loading, the platinum loading was changed to obtain catalysts of 0.5Pt / 10W / ASA, 1Pt / 10W / ASA, 1.5Pt / 10W / ASA, 2Pt / 10W / ASA, and 3Pt / 10W / ASA. Performance tests were carried out under the same catalytic reaction conditions as in Example 5, and their conversion rates and selectivities are as Figure 4 shown. It can be seen from the experimental results that the influence of the amount of platinum on the glycerol conversion rate and 1,3-propanediol selectivity shows a volcano-shaped rule. When the platinum content is 2%, the glycerol conversion rate and 1,3-propanediol selectivity are the highest.

[0081] To prove the excellent repeatability of the catalyst, a parallel test was carried out, specifically as follows:

[0082] Three 2Pt / 10W / ASA catalysts were prepared in parallel according to the preparation method described in Example 1, and the performance evaluation of the parallel samples was carried out according to the test method described in Example 3. The performance test results show that the glycerol conversion rate ranges from 75±3%, and the 1,3-propanediol selectivity ranges from 45±3%, indicating that the catalyst obtained by the method provided by the present invention has good repeatability.

[0083] In addition to the above embodiments, the present invention also includes other embodiments. All technical solutions formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of the present invention.

Claims

1. Preparation method of platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols, characterized in that: It includes the following steps: (1) Preparation of platinum colloid: Dissolve platinum salt in ethylene glycol to obtain solution A, dissolve sodium hydroxide in ethylene glycol to obtain solution B. Under stirring conditions, mix solution A and solution B evenly, adjust the pH value of the solution to 7 - 13, heat to 120 - 190 °C under the protection of an inert gas atmosphere and keep for 0.5 - 24 h, and obtain a platinum nano - colloid solution after cooling; (2) Preparation of tungsten trioxide colloid: Dissolve tungsten hexachloride in anhydrous solvent C, add water - containing solvent D, and when the solution changes from yellow to colorless or light blue, tungsten trioxide colloid is obtained; (3) After mixing the platinum colloid and the tungsten trioxide colloid, stir for a certain time, add silicoaluminate. After the platinum colloid and the tungsten trioxide colloid are loaded on the silicoaluminate, add water to precipitate the catalyst, and freeze - dry to obtain a platinum / tungsten trioxide / silicoaluminate composite; The mass ratio of the platinum colloid to the tungsten trioxide colloid is 1:0.05 - 1:50; the mass ratio of the platinum colloid to the silicoaluminate is 0.0005 - 0.20:

1.

2. The preparation method of the platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols according to claim 1, characterized in that: The platinum salt in step (1) is at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, and platinum acetate.

3. The preparation method of the platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols according to claim 1, characterized in that: The solvents C and D in step (2) are one or more of methanol, ethanol, propanol, butanol, ethylene glycol, and N,N - dimethylformamide.

4. The preparation method of the platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols according to claim 1, characterized in that: The silicoaluminate is amorphous silica - alumina or silicoaluminate molecular sieve.

5. The preparation method of the platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols according to claim 4, characterized in that: The amorphous silica - alumina is a composite composed of silica and alumina, where alumina accounts for 3% - 30% of the total mass of the composite; the silicoaluminate molecular sieve is ZSM - 5, NaX, or NaY.

6. A platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols, characterized in that: It is prepared by using the preparation method of the platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols according to any one of claims 1 - 5.

7. The platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols according to claim 6, characterized in that: In the platinum / tungsten trioxide / silicoaluminate composite, the mass percentage of platinum is 0.1% - 5%, and the mass percentage of tungsten trioxide is 2% - 40%.

8. Application of a platinum / tungsten trioxide / silicoaluminate composite for selective hydrogenolysis of polyols, characterized in that: Use of the platinum / tungsten trioxide / silicoaluminoxide composite for selective hydrogenolysis of polyols in the selective hydrogenolysis reaction of polyols as claimed in claim 6.

9. Use of the platinum / tungsten trioxide / silicoaluminoxide composite for selective hydrogenolysis of polyols as claimed in claim 8, characterized in that: the polyol is glycerol, erythritol, pentaerythritol or hexitol.

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